The present invention relates to a manufacturing apparatus which is used in a micro-gravity environment and which is directly and manually operated by a person in the micro-gravity environment.
The manufacturing of materials in a micro-gravity environment, such as in space, contributes considerably to the development of novel materials because materials can be manufactured which are difficult to manufacture on the ground under the influence of gravity. For example, in the biological engineering field, including protein engineering for designing molecular structures to create novel proteins having still higher functions, the manufacturing of bio-polymer crystals used as a sample for analyzing the structure and function of molecules, for example, crystals of protein or nucleic acid, is indispensable. When these bio-polymer crystals are manufactured on the ground under the influence of gravity, it is difficult to manufacture large crystals of high quality. Thus, it is expected that bio-polymer crystals will be manufactured using the micro-gravity environment of space.
If, however, these manufacturing apparatuses are all automated, it is difficult to obtain reliable results, particularly in the case of test manufacturing in which there are many indefinite factors. Thus, it is preferable that a person judges the situation and performs the appropriate operation. However, an experiment which is performed in space and which is intervened by the operation by a person becomes costly, the chances therefor are limited, and the limitations on the ease of operation are stringent. Thus, a manufacturing apparatus used in a micro-gravity environment is expected to perform a complete operation and must be provided with excellent ease of operation. In this connection, there has been a great demand for a manufacturing apparatus which is capable of reliably manufacturing materials and which is used in a micro-gravity environment in which ease of operation is excellent under a micro-gravity.
In a conventional manufacturing apparatus used to manufacture materials in a manned micro-gravity environment, for example, inside a manned artificial satellite, devices which are manually operated by a person are disposed on a horizontal plate surface. Such facility will be explained by using a manufacturing apparatus for manufacturing bio-polymer crystals as an example.
In this specification, the "horizontal" direction refers to such a direction from side to side and back and forth of the operator during operation when an operator, who takes a posture for performing an operation, is assumed to be standing or sitting vertically. Also, the "vertical" direction refers to a direction perpendicular to all the above-described horizontal directions, and is also simply called "vertical" or "up and down" without defining a reference.
Bio-polymer crystals are manufactured by mixing a precipitant solution with a bio-polymer solution in order to make the bio-polymer solution be supersaturated and by causing the bio-polymer crystals to become crystallized.
As the bio-polymer solution, a solution having salt reagents such as phosphate or acetate added as a buffer to a solution of a bio-polymer material, for example, protein, is usually used. As a precipitant solution, neutral inorganic salts of a high ion-strength, such as ammonium sulfate, cesium chloride, or sodium chloride, or organic solvents, such as polyethylene glycol, acetone, or ethanol, are usually used.
Although bio-polymer crystals are manufactured by mixing between a bio-polymer solution and a precipitant solution as described above, the reproducibility of crystal growth is not good because the binding force of the bio-polymer crystals is weak. Such poor reproducibility becomes a serious obstacle in an experiment under micro-gravity where the limitations of cost and chance are stringent. Because of this, a crystal manufacturing apparatus has been developed which is capable of reliably manufacturing crystals and is used in a micro-gravity environment by conducting a great number of experiments simultaneously at the same composition of materials and at the same growth conditions, or by varying the composition of the material or growth conditions little by little.
An apparatus for conducting such a number of experiments is usually constructed as follows.
FIG. 1 is a general view of the prior art, and shows a conventional apparatus for manufacturing polymer crystals, which is used in a micro-gravity environment. Referring to FIG. 1, a block 181a has one or more cells which are provided with a portion where a manufacturing experiment is carried out, for example, a crystallization chamber where bio-polymer crystals are grown. The block 18(a) is replacably mounted on a plate-like cell mount 182. The whole of the cell mount 182 on which the block 181a is mounted constitutes a plate-like-shaped manufacturing unit 18 in the sense that the entire shape has the obverse and reverse surfaces. This manufacturing unit 18 is horizontally inserted into a housing section 17 from the front of the crystal manufacturing apparatus in such a way that a drawer is housed. A front plate 183, which is perpendicular to the cell mount 182, is usually securely disposed in the forward (the portion near the front of the apparatus during housing) tip of the cell mount 182. The front plate 183 covers the opening of the housing section 17 on the front panel of the apparatus. That is, the manufacturing unit 18 ordinarily constitutes a drawer-like construction having the cell mount 182 as the bottom plate. Further, a plurality of housing sections 17 are often disposed in the crystal manufacturing apparatus, and a great number of cell mounts 182 are mounted in the housing sections 17.
The cell mount 182 inserted into the facility is held inside a constant-temperature tank 19 or a thermostat which is surrounded by a thermal insulation material so that the cell mount 182, in a set of one or more, is maintained at a predetermined temperature at which crystals must be grown and stored.
A manufacturing apparatus having such construction has a great number of portions where a manufacturing experiment is carried out, for example, crystallization chambers, and further, the portion where a manufacturing experiment is carried out can be replaced with a new one by replacing the block 181a. Accordingly, it is possible to conduct a great number of manufacturing experiments easily by using one crystal manufacturing apparatus.
However, in the conventional manufacturing apparatus, as in a bio-polymer crystallization apparatus of FIG. 1, the cell mount 182 is horizontally mounted in the housing section 17 disposed in the front panel 11 of the apparatus. However, in the conventional construction in which the manufacturing unit 18 having an operation mechanism, such as the cell mount 182, is horizontally mounted, the surface side on which the device, in which a manufacturing experiment is carried out, is mounted becomes an operation side where the operation is performed. Hence, the following problem occurs.
When a person works in a room in a micro-gravity environment, such as in a manned artificial satellite, it is common that his legs and one of his hands are fixed, and the operation is performed by the remaining free hand. To secure the fixed positions of his hands and feet, the vertical direction is set in the room. Because of this, the apparatus employed in a micro-gravity environment is manufactured and used by defining the vertical direction thereof, so that the apparatus has it's top and bottom. That is, such apparatus is designed so that the operator operates the facility with one hand while looking at the apparatus from in front and above the apparatus.
Since in the conventional apparatus having the manufacturing unit 18 mounted horizontally thereon it is impossible to view the rear surface of the manufacturing unit 18 from above, it is difficult to operate an apparatus disposed on the rear surface of the manufacturing unit 18. For this reason, all apparatuses to be operated, for example, the blocks 181a, are preferably disposed on the top surface of the manufacturing unit 18.
However, the housing section 17 is usually disposed inside the constant-temperature tank 19. Because of this, if the apparatuses to be operated are disposed on the top surface of the manufacturing unit 18, for example, on only the top surface of the cell mount 182, the symmetry of the manufacturing unit 18 deteriorates, and the thermal design of the constant-temperature tank 19 for housing the manufacturing unit 18 becomes difficult.
It is desired, in addition to the above-described construction, that means for observing the process or result of the experiment, for example, the process or result of the crystallization be disposed to increase the efficiency of the experiment. Such observing means is accomplished, for example, by using a block made of a transparent material and by observing it using a CCD camera from outside the constant-temperature tank through a window provided therein. However, the window provided in the constant-temperature tank is inferior in thermal insulation characteristic. Accordingly, it is difficult to make the temperature distribution inside the constant-temperature tank uniform.
Another problem which occurs when the manufacturing unit is mounted horizontally is that it is difficult to reduce the number of observation facilities, which are observing means, and to reduce the volume and weight of the apparatus. That is, in the conventional apparatus in which the above-mentioned manufacturing unit is mounted horizontally, the devices to be operated and the devices to be observed are disposed on the top surface of a manufacturing unit which can be checked visually and which is easy to operate. For this reason, one observation facility must be disposed for each cell mount. Because of this, the number of observation facilities is not reduced, and therefore the volume and weight of the apparatus is not reduced.
To solve such problem, a bio-polymer crystal manufacturing apparatus having one observation facility for observing a plurality of the device to be observed which are disposed on one surface of the above-mentioned manufacturing unit, for example, a great number of cell mounts, has been invented and is disclosed in Japanese Patent Laid-Open No. 4-367599. Referring to FIGS. 2 and 3, in this apparatus, blocks 310 having an observation window 312 for observing in a crystallization chamber 311 housed in the block 310, the temperature of which is controlled individually, are arrayed in such a way that the observation windows 312 are aligned in the form of a two-dimensional lattice. The observation facility has an observing unit 320 having a CCD camera 321 mounted thereon which is driven by a scanning motor 330 and scanned two-dimensionally, and observes the crystallization chamber 311 from the observation windows 312 which are arrayed two-dimensionally. A mirror 323 is used to observe the observation window 312 in a direction at right angles to the optical axis of the CCD camera 321. An illumination unit 322 is moved vertically together with the CCD camera 321 and illuminates the crystallization chamber 311 through the observation window 312.
In this apparatus, to maintain respective blocks 310 each at a different temperature, each block 310 is thermally insulated, and thus each block forms one constant-temperature tank. However, since in this construction the observation window 312 causing an inferior heat insulation effect is required in one of the blocks 310, it is difficult to make the temperature distribution in the block 310 uniform. Furthermore, to make the COD camera 321 perform two-dimensional scanning, two long arms which intersect crosswise and scan vertically and horizontally by the scanning motors 330, respectively, are required. For this reason, it is difficult to form the facility of a strong construction which can withstand the vibrations which occur during a launching of the apparatus into a space environment or during a return to the ground from a space environment.